Electrical stimulation puts bounce back in step after stroke

Electrical device helps stroke, MS victims walk

Published: Monday, July 11 2011 9:50 p.m. MDT

Without the neurostimulator strapped to her leg, Nancy Powell would experience foot drop, in which the toes do not raise from the floor when a step is taken, increasing the risk of a fall.

Laura Seitz, Deseret News

SALT LAKE CITY — When Nancy Powell's walking along, the residual effects of a stroke seven years ago following a severe car crash are well hidden.

Her partially paralyzed right hand is tucked away in her pocket. And the medical device that provides low-level electrical stimulation to get her to pick up the toes of her right foot is buried inside her shoe, the transmitter hidden by her pant leg. Neurostimulation has put some bounce in her step.

Without that stimulation from the NESS L300, made by Bioness, Powell has "foot drop," a common aftermath of such neurological events as stroke, multiple sclerosis and traumatic brain injury. Because foot drop leaves people dragging their foot or failing to pick up their toes, they walk more slowly and with less stability. The risk of tripping or falling are greater.

But the device, which is small and lightweight and sits in the heel of a shoe, responds to the pressure of the foot during walking. When the heel comes down on it, it interrupts the flow of the functional electrical stimulation to the lower part of her leg, causing her to flex her foot.

With the device, she's also built enough muscle through activity using it that she can even walk for a while without difficulty, although when she grows tired or goes without it for a long period of time, the foot drop reappears.

The University of Utah School of Medicine is conducting a stroke rehabilitation research study, using the new NESS L300TM, which has already been cleared by the Food and Drug Administration (FDA) for use in stroke rehabilitation. Participants must have had their stroke more than three months ago, be 18 or older and not have a metallic implant, among other requirements. For information, call 801-585-6998 or email mary.annis.pautler@hsc.utah.edu.

On July 5, 2004, Powell and her husband, Larry, were involved in a head-on collision. He can't remember the crash, though every detail is etched in her mind. He suffered broken ankles and a crushed heel; she suffered various injuries including a serious broken femur that has left one leg an inch shorter than the other. In surgery to repair it, she suffered complications from a previously undiagnosed heart defect that triggered several strokes. She was placed in a drug-induced coma for more than a month, before she was moved to a rehabilitation center, where she learned to speak and walk and function again.

She was just 43 years old when she had the strokes.

About 2.5 million people worldwide have multiple sclerosis, 780,000 people have a stroke each year and 1.4 million have a traumatic brain injury. There are also roughly 200,000 people who live with a spinal cord injury. Those can all result in foot drop.

Nearly two years ago, Powell joined a clinical study of the NESS L300. With it, she could walk nearly normally and she missed it when the study was over. It took a year to get the device approved through the Veterans Administration, from which she receives her health care after a 13-year career in the U.S. Army.

Typically, a patient with foot drop might use an ankle-foot orthosis, more commonly called an AFO, said Randy Carson, a physical therapist at University Hospital.

That's a plastic brace that holds the foot rigid and keeps the toes from lagging when the foot is raised. And the AFO still is the better option for some patients, such as those who have certain kinds of knee problems.

But increasingly, physical therapists use neurostimulation for foot drop, including right after stroke occurs to try to head it the foot issue off completely, he said. "We use it a lot, even with in-patients," he said. "We try to see if we can break the cycle right away and hopefully avoid therapy and a brace."

Whether using it will eventually retrain a patient enough to not need it is subject to debate, he said.

One of the big advantages to electrical stimulation is that the muscle gets stronger. "It makes you do the work," said Carson. Anyone in a brace is going to get weaker where he or she is braced.

Carson believes time will sort its users into two categories: Those whose brains and muscles retrain so they don't need the electrical stimulation long-term and those who will have foot drop whenever they're not using the device. But it's too new to have long-term results pinned down.

The transmitter is placed so it stimulates her nerves on a band that's a stroke friendly design which can be added or removed one-handed and sits just below the knee. At night, Powell takes off the transmitter and plugs it into a charger.

Carson notes that when Powell shuts it off and walks briefly, she does much better than he would have predicted. But most, he suspects, would "immediately go back to foot drop."

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